1. Field of the Invention
This invention relates to gratings, and in particular to a quick-release grating.
2. Background of the Invention
In today's security-conscious world, gratings have become a common architectural feature in residences and commercial buildings alike. The incidence of burglaries, home invasions and thefts which has occurred in this century has contributed to a desire for protection against unwanted building entries. As a result, many windows feature sturdy gratings made of metal bars welded into a frame, which cover a window or other building aperture, and prevent entry by a burglar, who could otherwise gain entrance merely by breaking the window glass.
An unfortunate side effect of the existence of window gratings is their converse ability to prevent building occupants from exiting through the barred window in an emergency, such as a building fire. It is a sad irony that every year individuals are trapped inside burning buildings by the very window gratings which were supposed to protect them.
Thus it has become extremely important to provide a grating quick-release which on the one hand is secure enough to prevent burglaries, yet on the other hand is capable of quick, reliable release. In this fashion, building occupants would be provided an escape route through building apertures equipped with a grating quick-release, and yet when the apertures they cover are not being used as exits, the gratings would prevent unwanted entry by burglars and thieves.
Existing Designs
A number of devices capable of releasing a grating have been proposed. U.S. Pat. Nos. 3,913,957, 4,243,090 and 5,657,578 were granted Astie et al., Kemp, and Thompson respectively. While these devices provided a means of releasing a security grating, it was possible for a burglar to break the window glass and introduce a hand or tool through the grating and open the grating. Needless to say, this design shortcoming defeated the very purpose for installing a security grating in the first place.
U.S. Pat. Nos. 4,476,957 and 5,603,183 were granted Ory and Giovinazzi respectively. These devices combined a ladder function with a security grating, and appear to have been designed for a second floor (or higher) window. Although means to release the grating was taught, the release mechanism in both cases required substantial vertical clearance below the window upon which the grating was mounted. Where such substantial vertical clearance did not exist, it would be difficult or impossible to open the grating in case of fire.